Science To Support the Understanding of South Texas Surface-Water and Groundwater Resources in a Changing Landscape

By Darwin J. Ockerman, Travis J. Garcia, and Stephen P. Opsahl

Against a backdrop of constant cycles of extreme hydrologic conditions ranging from oppressive droughts to life-threatening floods, the water-resource landscape of south Texas is undergoing constant change. Demands on water resources are increasing because of changes related to population growth, energy demands, agricultural practices, and other human-related activities. In south Texas, the Nueces, San Antonio, and Guadalupe River Basins cover approximately 50,000 square miles and include all or part of 45 counties. These stream systems transect the faulted and fractured carbonate rocks of the Edwards aquifer recharge zone and provide the largest sources of recharge to the aquifer. As the streams make their way to the Gulf of Mexico, they provide water for communities and ecosystems in south Texas and deliver water, sediment, and nutrients to the south Texas bays and estuaries.

The U.S. Geological Survey (USGS) works in cooperation with other local, State, and Federal agencies to provide timely access to water data, publications, and information to foster a better understanding of the water resources of south Texas. The USGS and our cooperators are involved in a wide variety of programs for collecting hydrologic data and scientific information in the changing landscape of south Texas to help our cooperators effectively address water-resource issues in this part of the State. This fact sheet provides an overview of our collaborative scientific endeavors in the basins of the Nueces, San Antonio, and Guadalupe Rivers and lower Rio Grande. An overview of USGS capabilities pertaining to water resource issues in Texas, including recently completed and ongoing studies in south Texas, is available at http://tx.usgs.gov/Capabilities/index.html.

Sediment Monitoring in the Lower San Antonio and Guadalupe Rivers
Quantities and Sources of Suspended Sediment to Coastal Bays and Estuaries
Agricultural Runoff in the Texas Coastal Bend
Contaminants in Streambed and Suspended Sediments in the San Antonio Area
Assessing the San Antonio River Watershed for Possible Contaminants from Hydraulic Fracturing Fluid and Water Produced by Oil and Gas Activities

Pharmaceutical Compounds, Hormones, and Other Emerging Contaminants in the San Antonio River Basin, South Texas
National Water-Quality Assessment Program
References